Dexamethasone inhibits Mycobacterium tuberculosis-induced glycolysis but preserves antimicrobial function in primary human macrophages.

Human macrophages were left untreated or treated with vehicle control (ethanol, 0.02%) or dexamethasone (0.05-5 μM, as indicated). To model pathways of cellular death, MDM were treated with staurosporine (1 μM) for 24 h. The effects of dexamethasone on macrophage metabolism was examined by Seahorse metabolic flux analysis using the glycolytic rate assays and Mitostress tests (Excel sheet 1 – labelled Figure 1 hMDM, Excel sheet 2 – labelled Figure 2 hAM, Excel sheet 3 – labelled Figure 3 hMDM).

The expression of mRNA transcripts of metabolic enzymes were assessed to support the functional metabolic data (Excel sheet 1 – labelled Figure 1 hMDM, Excel sheet 3 – labelled Figure 3 hMDM). The ability of dexamethasone to alter the secretion of cytokines IL-1β, TNF, IL-6, IL-8 and IL-10 was assessed in supernatants from uninfected and Mtb infected (H37Ra) macrophages (Excel Sheet 4 – labelled Figure 4 hMDM). The effect of dexamethasone cell death and caspase activation in macrophages was examined (Excel Sheet 5 – labelled Figure 5 hMDM).

Finally bacterial control of macrophages was examined in dexamethasone treated macrophages in the presence of bafilomycin or rapamycin. Bafilomycin A1 (50 nM) or rapamycin (250 ng/ml) were used to examine the role of autophagy in dexamethasone induced bacterial control (Excel Sheet 6 – labelled Figure 6 hMDM). These data were calculated by assessing colony forming units assays on Middlebrook agar.

Supplemental Figures 1 and 2 are supporting data for Seahorse Assays (Excel Sheet 7- labelled Figure S1 hMDM, Excel Sheet 8- labelled Figure S2 hMDM). Supplemental Figure 3 is supporting data for bacterial growth assays demonstrating phagocytosis on day 0 (Excel Sheet 9- labelled Figure S3 hMDM).